This invention relates to a method, application of the method and a layer structure for determination of a substance.
Chemical sensors for the determination of chemical substances (so-called analytes) in samples or specimens comprise a whole range of thermodynamically reversible or regenerable measuring probes. Such probes must include at least one recognizing element, at least one transducer element, and, ideally, at least one calculation/display element. The recognizing element usually is implanted in a layer structure; the analyte is selectively isolated from other substances in the sample/specimen and extracted into the layer. Recognition molecules are also referred to as host molecules and are capable of selectively recognizing the analyte, which may be referred to as guest molecule. The process of recognition, the interaction between host and guest molecule, leads to a quantifiable signal which is obtained in a transducing process. Biosensors represent a subgroup of chemical sensors in which the recognizing element is a biologically active substance, such as enzymes, peptides, receptors, antibodies, cell organelles, etc.
Chemical sensors and biosensors feature a growing development potential and are of increasing importance in analytics (analyses in the fields of environmental and food technology, medicine and biotechnology). The characteristics of such sensors are:
inexpensive and rapid analyses, PA1 continuous measuring directly in the specimen, PA1 mobility of probes and measuring systems, PA1 use in isolated locations and high-risk sites, PA1 selective use of specifically tailored systems. PA1 2.2.1 by immobilization on the surface of the supporting medium (electrostatic, covalent, and adhesive interactions, etc.); they may be brought into contact with both nonpolar and polar phases (Hall, G. F., Turner, A. P. F., J. Cell. Biochem., Suppl. 14B (1990) 345; Hall, G. F. et al., Anal. Chim. Acta 213 (1988) 113-119). PA1 2.2.2 by incoporation into polar or nonpolar bulk membranes, so that molecular recognition takes place in or next to the boundary face rather than on the surface of the membrane. Relevant examples have been described in various publications (Seiler, K., Simon, W., Anal. Chim. Acta, 266 (1992) 73-87; patent publications EP-A-0153641, JP-A-2082152). PA1 2.3.1 for ions and charged molecules: PA1 2.3.2 for uncharged, charged, or neutral molecules: